U.S. Pat. No. 5,328,331 discloses an airfoil comprising an integrally formed double shell outer wall surrounding an inner cavity. Airfoils of this type have been developed to increase engine efficiency by maximizing cooling efficiency. However, airfoils of this type can be difficult to manufacture, and spacing between the outer and inner walls is generally too great, which may reduce cooling efficiency. Additionally, it may be undesirable to form the integral outer and inner walls from a common material.
Metal injection molding can be used to produce components having complex geometric shapes. Finished parts produced by metal injection molding can exhibit mechanical properties near those of the base material in its wrought form and can have densities approaching those of the base material.